Theoretical mechanisms for synthesis of carcinogen-induced embryonic proteins: X. Correlation of the induceability of hepatomas and alpha-fetoprotein gene activity.

We have observed a distinct difference in the alpha-fetoprotein production of Sprague-Dawley rats and Swiss white mice. When both animals are fed a 1% D/L-ethionine diet, only the rat responds with increased levels of hepatic alpha-fetoprotein synthesis as shown by radioimmunoassay studies. Also, hybridization studies, with a complementary deoxyribonucleic acid for alpha-fetoprotein messenger ribonucleic acid, proved negative for the mouse, even after forty days on the 1% D/L-ethionine diet. This evidence, combined with other information leads us to believe that the mouse has a genomic regulatory system that is resistant to carcinogenic change by certain chemicals. Furthermore it may eventually be proven that hepatic tissue that is competent to have certain embryonic genes activated may also be capable of becoming neoplastic.